/* 初始化样式，清除默认边距等 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: "微软雅黑", sans-serif;
    background-color: #f4f4f4;
}

/* 头部导航样式 */
.header {

    border-bottom: 1px solid #ddd;

}

.header-inner {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 0;
    height: 100px;

}

.header-inner img {
    width: 200px;
    height: 40px;
    object-fit: fill;
    vertical-align: middle;
}

.logo {
    font-size: 24px;
    color: #00a2e8;
    font-weight: bold;
}

.nav ul {
    display: flex;
    list-style: none;
}

.nav li {
    margin: 10px 45px;
    padding: 5px;
    border-bottom: 2px solid transparent;
}

.nav li:hover {
    border-bottom: 2px solid #32b7ff;
}

.nav a {
    text-decoration: none;
    color: #333;
}

.search {
    display: flex;
    align-items: center;
    border-radius: 8px;
    background-color: rgb(216, 216, 216);
    height: 35px;
}

.search input {
    height: 100%;
    padding: 0 10px;
    border: none;
    outline: none;
    border-radius: 8px;
    background-color: rgb(216, 216, 216);
}

.search button {
    width: 30px;
    height: 30px;
    border: none;
    background: url("../image/搜索.png") no-repeat center;
    cursor: pointer;
    background-size: 100% 100%;
    opacity: 0.5;
}

.user {
    color: #333;
}

.user img {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    object-fit: fill;
    vertical-align: middle;
}

.user>span {
    font-weight: 500;
    margin-left: 10px;
}

/* 主体内容容器 */
.main {
    width: 1900px;
    margin: 0px auto;
    display: flex;
    flex-wrap: wrap;
}

/* 左侧侧边栏样式 */
.sidebar {
    position: absolute;
    width: 200px;
    background-color: rgba(0, 0, 0, 0.5);
    left: 18%;
}

.sidebar ul {
    list-style: none;
}

.sidebar li {
    border-bottom: 1px solid #485b6e;
    align-items: center;
    padding-left: 20px;
    background-image: url(../image/right.png);
    background-repeat: no-repeat;
    background-position: 175px center;
}

.sidebar li:hover {
    background-image: url(../image/right-hover.png);
}

.sidebar li:hover a {
    color: #32b7ff;
}

.sidebar a {
    display: block;
    color: #fff;
    text-decoration: none;
    padding: 12px 15px;
}

/* banner及我的课程表区域样式 */
.banner-section {
    height: 415px;
    width: 100%;
    display: flex;
    color: #fff;
    position: relative;
    background-image: url(../image/banner.png);
    background-position: center center;
    background-repeat: no-repeat;
    background-size: fill;
    background-color: rgb(0, 146, 203);
}

.banner {
    flex: 1;
    display: flex;
    align-items: center;
}

.banner-text p {
    margin-bottom: 10px;
    line-height: 1.6;
}

.banner-text h2 {
    font-size: 28px;
    line-height: 1.4;
    margin-bottom: 15px;
}

.banner-img {
    flex-shrink: 0;
    margin-left: 20px;
}

.img-placeholder {
    width: 200px;
    height: 120px;
    background-color: rgba(255, 255, 255, 0.3);
}

.my-courses {
    position: absolute;
    top: 10%;
    left: 70%;
    width: 220px;
    height: 80%;
    background-color: #32b7ff;
    border-radius: 5px;
}

.my-courses h3 {
    font-size: 18px;
    margin: 10px;
}

.my-courses ul {
    background-color: #fff;
    list-style: none;
    border-radius: 10px;
    padding: 10px;
    height: 290px;
}

.my-courses li {
    margin-bottom: 8px;
    line-height: 1.6;
    color: #333;
    font-weight: 500;
    padding-bottom: 10px;
    font-size: 15px;
    border-bottom: 1px solid #ddd;
}

.my-courses li:last-child {
    margin-top: 20px;
    border-bottom: none;
    background-color: #32b7ff;
    border-radius: 20px;
    text-align: center;
    color: #fff;
    padding-top: 6px;
}

.my-courses li>span {
    margin-top: 10px;
    color: #00a2e8;
}

.all-courses-btn {
    width: 100%;
    padding: 8px;
    background-color: #00a2e8;
    color: #00a2e8;
    border: none;
    cursor: pointer;
}

/* 精品推荐标签栏样式 */
.tags-section {
    width: 1215px;
    background-color: #fff;
    margin: 20px auto;
    height: 60px;
    box-shadow: 0px 5px 10px #989898;
}

.tags {
    display: flex;
    list-style: none;
    justify-content: space-between;
    align-items: center;
    padding: 10px;
    height: 100%;
}

.tags li {

    margin-right: 15px;
    cursor: pointer;
    color: #333;
}

.tags li:nth-child(n+2) {
    padding: 3px 20px;
    border-right: 1px solid #ddd;
}

.tags li:last-child {
    border: none;
    color: #32b7ff;
}

.tags li.active {
    color: #00a2e8;
    font-weight: bold;
}

.modify-interest {
    color: #00a2e8;
    margin-left: auto;
}

/* 精品推荐课程列表区域样式 */
.courses-section {
    width: 1215px;
    margin: 0 auto;
    padding: 15px;
    margin-top: 10px;
}

.section-title {
    font-size: 18px;
    margin-bottom: 10px;
    display: inline-block;
}

.view-all {
    text-decoration: none;
    color: #00a2e8;
    float: right;
}

.courses-list {
    display: flex;
    flex-wrap: wrap;

    margin: 10px auto;
}

.course-item {
    width: 18%;
    margin-right: 1%;
    margin-left: 1%;
    margin-bottom: 20px;
    background-color: #fff;
    border: 1px solid #eee;
    text-align: left;
}

.course-img {
    margin-bottom: 10px;
}

.img-placeholder {
    width: 100%;
    overflow: hidden;
}

.img-placeholder img {
    width: 100%;
    object-fit: fill;
    vertical-align: middle;
}

.course-item>.course-hs {
    padding: 10px;
    background-color: #fff;
}

.course-item>.coures-hs>h4 {
    margin-bottom: 10px;
    margin: 5px;
}

.course-item>.coures-hs>span {
    margin-bottom: 10px;
    display: inline-block;
    margin: 5px;
    color: coral;
}

.course-item>.coures-hs>span>em {
    color: #333;
}

.course-item p {
    color: #999;
    margin-bottom: 5px;
}